1. Field of the Invention
The present invention relates generally to a climate control system for passenger vehicles and, more particularly, to means for controlling the operation of the blower system of a motor vehicle heating, air conditioning, and ventilation system in accordance with outside ambient air temperatures, passenger loading, and the return air temperatures of the system.
2. Description of the Prior Art
Systems for heating, cooling, and ventilating a highway bus, coach, or other passenger vehicle are, of course, well known and it is believed that the apparatus disclosed by E. T. Todd in U.S. Pat. No. 3,008,694 can be considered a representative example of the prior art. It is also known to provide blower control means for passenger buses and the like to regulate the output of the temperature and ventilation control blowers to condition the air in the passenger compartment. Examples of prior teachings of such control means are shown by H. E. Norviel and R. W. Pachaly in U.S. Pat. Nos. 1,941,363, and 1,091,012, respectively, who disclose apparatus for turning on an electric fan automatically to circulate air in the passenger compartment when the vehicle is moving slowly or when it is at a standstill; T. J. Lehane et al., U.S. Pat. No. 2,667,336, who discloses apparatus for conditioning air in a passenger compartment in accordance with the heating and cooling load relative to the capacity of the heating and cooling apparatus; and A. R. Clark, U.S. Pat. No. 3,075,449, who teaches means for controlling the heating and ventilating blower in accordance with the speed of the vehicle and the temperature within the operator's compartment. It will be appreciated; however, that none of the enumerated prior art discloses means by which the blowers of the system are controlled in accordance with ambient temperatures, passenger load, and return air temperature of the system such that the volume and temperature of the air used to comfort-condition the passenger compartment of a vehicle can be regulated precisely and efficiently. It is seen also that F. J. Troll, in U.S. Pat. Nos. 1,147,128 and No. Re 14,475, shows that it is known to sense the load on a motor vehicle, but there is nothing in Troll's disclosures that teach the utilization of the signal produced by his load sensing apparatus to control a blower in a climate conditioning system for the vehicle.
Inasmuch as none of the prior art blower control means for vehicle heating, cooling, and ventilating systems sense outside ambient temperatures, passenger loading, and return air temperatures of the system to deliver air at an optimum temperature and volume to the passenger compartment of the vehicle, it is seen that their efficiency suffers thereby and the present invention offers an improvement over the prior art that meets the exacting standards of the present day passenger vehicles.